But Vollmer stepped into the starting lineup as a rookie, where he has remained ever since. And four years later, he’s the only one of the group still with the Patriots.

That will continue to be the case. After testing the free agent waters and finding them tepid, he signed a four-year extension Tuesday that could be worth $27 million.

“I’m just happy to be here; this is the place I wanted to be,” Vollmer said Thursday during a conference call. “I’m still here and I think ‘thankful’ would describe it most. I’m just really thankful for Mr. (Robert) Kraft and his family and Coach (Bill Belichick) and whoever else was involved to let me be a part of this and to give me an opportunity so I can continue to prove myself. Excited and happy to be here, I guess.”

The 6-foot-8, 320-pound Vollmer has the ability to play both tackle positions and was recognized for his exemplary work by being named a second-team All-Pro in 2010. But he has dealt with back and knee injuries the last two seasons that caused him to miss 11 games and affected his play in a number of others.

That led to a lack of interest by other teams in the unrestricted free agent and, in turn, a team-friendly offer from the Patriots that Vollmer ultimately accepted.

Vollmer received a $7 million signing bonus and his base salaries for four years total a modest $7.75 million. The other $13-plus million is tied to playing and performance incentives.

If he remains healthy, he’ll be paid accordingly.

“I’m not going to go into details about what the contract is,” said Vollmer, who also took a pass on revealing which, if any, teams he visited since free agency began March 12. “I think I’m just happy to be here. Obviously, you go into a season and you’re trying to be healthy. You do everything you can. Sometimes you can’t help it; other things you can prevent with certain preparation.

“Obviously, as players, we do everything we can to stay healthy and prepare ourselves for the contact and physicality of the sport. I’ve continued to do that.”

Vollmer’s return means the Patriots will enter next season with all five starters back from a line that did a commendable job of protecting quarterback Tom Brady. The rest of the blockers: left tackle Nate Solder, left guard Logan Mankins, center Ryan Wendell and right guard Dan Connolly.

“I certainly like it, obviously,” Vollmer said of the consistency that comes with continuity. “When you play next to a guy for a few years and you practice next to a guy, you just get certain things down. You kind of know how the other guys play certain situations and you just get a feel for each other. I think that is important.”

One player who won’t be back for the Patriots is receiver Wes Welker, who signed with the Denver Broncos after getting the cold shoulder in New England.

“You know, I don’t know what happened and I’m not willing to talk for him or for anyone else,” Vollmer said. “But obviously he’s a great football player and I really enjoyed playing with him and over the years, just seeing what he can do, and I wish him all the best.”

The Patriots signed free agent receiver Michael Jenkins. Drafted 29th overall out of Ohio State in 2004, Jenkins played for the Vikings the last two seasons after spending his first seven NFL seasons with the Falcons. He had 40 receptions for 447 yards and two touchdowns in 16 games last season.